1. Field of the Invention
The invention relates to tape cartridges adapted for the magnetic recording of information and more particularly to an improved cartridge of increased tape capacity.
2. Description of the Prior Art
For many years, magnetic recording tape has been utilized as an inexpensive and reliable medium for the storage and retrieval of data processing information. It has become the practice that for small scale applications, tape cassettes and tape cartridges have proven to be successful vehicles for easy loading for the magnetic tape onto a suitably adapted tape drive Moreover, said cassettes and cartridges protect the magnetic recording tape from contamination and/or inadvertent contact during operation within the tape drive as well as during storage outside of the tape drive. Such wide acceptance has been received for tape cassettes and tape cartridges that standard configurations have been adopted by the data processing industry.
One such data tape cartridge which has received wide industry acceptance and customer usage is a cartridge similar to that disclosed in U.S. Pat. No. 3,693,255 to Von Behren. The Von Behren patent discloses a tape cartridge wherein two packs, having magnetic recording tape wound therebetween, are driven by an elastic belt disposed for contact with said reels with said belt being driven by a driving roller. Various manufacturers of tape cartridges and tape drives have adopted a configuration similar to the Von Behren patent as a standard configuration. Also, the cartridge-drive interface opening within various commercially available tape drives has been adapted for receipt of the standard cartridge. This standard configuration is expressed in ANSI (American National Standards Institute) specification X3.55-1977 [Unrecorded Magnetic Tape Cartridge for Information Exchange, 0.025 (0.30 mm), 1600 bpi (63 bpmm), phase encoded]. Thus, manufacturers wishing to market a tape cartridge for such a tape drive must do so with cartridge compatibility as a primary design consideration. However, adoption of a standard cartridge configuration creates a common problem in the data processing industry. The problem centers around increasing the tape capacity within the physical constraints of the cartridge compatibility. This can be a most difficult task.
Another tape cartridge which has received industry acceptance is similar to that disclosed by U.S. Pat. No. 3,907,230 to Merle et al. Merle et al describes a tape cartridge that has become known in the art as a "flowing roller" cartridge. In a so-called floating roller cartridge, the tape is driven by an endless elastic belt which moves without slippage in contact with the two tape packs of the cartridge (a take-up pack and a supply pack). The belt is disposed about two rollers, a driven roller and a floating roller. The driven roller is rotatably mounted to a fixed pivot within the cartridge adapted to receive rotation from a driving member located within a cartridge tape drive which is appropriately designed to receive said floating roller cartridge. The position of the floating roller within the tape cartridge is determined by the amount of tape wound on each respective tape pack because the elastic belt captures the floating roller urging it into intimate contact with each tape pack. In this manner, the belt makes contact with each tape pack over some predetermined angle of wrap permitting reliable, nonslip drive. However, floating roller tape cartridges of the prior art suffer from the same practical problem as the Von Behren tape cartridge to the extent that as a tape cartridge design becomes standardized with respect to a cartridge tape drive interface, increasing the storage capacity of the tape cartridge is severely constrained.
In order to increase the tape capacity of a cartridge of a configuration similar to that disclosed in the Von Behren and Merle et al patents, some increase in length of tape wound between the two hubs may be obtained by decreasing the thickness of said tape or reducing the diameter of the hubs. In this manner, it has been possible in some instances to increase the tape capacity of a standard cartridge by approximately 100%. Other than the method of winding more tape of decreased thickness upon the or reducing the diameter of the hubs, no other techniques are known in the prior art for increasing the capacity of a magnetic tape cartridge while maintaining the cartridge/drive standard interface.